Electronic thermostats are slowly replacing the mechanical thermostats utilized in the past. However, electronic thermostats have one inherent problem which was not present in the earlier mechanical thermostats. This problem arises when the power source to the electronic thermostat no longer provides power to the thermostat and the thermostat no longer functions. In electronic thermostats, this commonly happens when the batteries which provide power to the thermostat are discharged to such a point that they can no longer operate the thermostat. When the thermostat no longer operates, the heating system also no longer operates, as the thermostat does not complete the circuit that allows for the heating relay to turn on the heating system. Thus, when the batteries in the battery powered thermostat go dead, the thermostat becomes inoperative. As a result, no heat is provided to the controlled space. In climates where the temperature drops below freezing, a problem exists with pipes freezing and possibly rupturing which can damage the space which is being controlled by the thermostat. In prior systems, bimetal switches have been placed across the thermostat contacts. They are then set at a level that will not interfere with the normal thermostat operations. This means in normal operations, the bimetal switch would not be allowed to activate until the temperature dropped to a temperature of approximately 40 F. If the bimetal switch is set at a higher setpoint, the bimetal switch would interfere with the operation of the thermostat if the thermostat was set to its lowest setting. Further, if the bimetal switch is set to maintain at least 40 F, there is a strong possibility that the temperature of the outside walls could drop to 32 F or less. Any pipes contained in these walls could freeze and possibly burst. The present invention provides circuitry to utilize a bimetal switch at a higher setpoint when battery power is low or nonexistent.